Method and device for forming multi-curved glass sheet

ABSTRACT

This invention relates to forming a complex shape glass ( 10 ) by bending a horizontal sheet glass ( 21 ) in a longitudinal direction and a cross direction. As a heated sheet glass pinched by multiple straight rollers ( 30, 30 ) consisting of upper-lower pairs disposed on a curved conveying path is carried in a downstream direction the sheet glass is bent along the curved conveying path. In a next step, the sheet glass curved in the conveying direction is bent in the conveying direction and in a direction perpendicular to the conveying direction by a convex forming roller with its center bulging in a curve ( 33, 35, 83 ) and a concave forming roller with its center waisted in a curve ( 34, 36, 82 ), and a complex shape glass is obtained.

TECHNICAL FIELD

This invention relates to a complex shape sheet glass forming method andapparatus, and particularly to a complex shape sheet glass formingmethod and apparatus suited to a side window glass of an automobile.

BACKGROUND ART

As methods for bending sheet glass, many methods of bending a sheetglass in a conveying direction while the sheet glass is pinched andcarried by upper and lower straight rollers are known.

As a specific example, upper and lower straight rollers are disposedabove and below each other separated by a gap approximately the same asthe thickness of the sheet glass, and multiple such upper and lowerstraight rollers are arrayed so as to curve in a direction of advance ofthe sheet glass. That is, multiple straight rollers are arrayed on aconveying path formed in the shape of a curve. The method of bending asheet glass heated to near its softening point in the conveyingdirection by pinching while conveying it with upper and lower straightrollers is known.

This bending method makes it possible to bend a sheet glass with a highforming accuracy, and also as continuous production is possible itoffers excellent productivity.

A method for obtaining a complex shape glass by heating a sheet glass tonear its softening point and then pinching this sheet glass with upperand lower curved rollers and bending the sheet glass in a conveyingdirection and a direction perpendicular to the conveying direction(hereinafter called “conveying face width direction”) is also known.

This complex shape sheet glass forming method is proposed in for exampleJP-A-54-85217, titled “Method and Apparatus for Forming Sheet glass byRolling”, and JP-A-3-174334, titled “Machine and Method forManufacturing a Curved Sheet Glass”.

The complex shape forming method disclosed in JP-A-54-85217 will bedescribed on the basis of FIG. 13A and FIG. 13B.

Multiple pre-forming rollers 100 of the kind shown in FIG. 13A arearrayed on a conveying path with a downward gradient so as to curve onthe downstream side of a heating furnace, and a sheet glass 101 heatedto near its softening temperature in the heating furnace is carried bythe multiple pre-forming rollers 100. Each of the pre-forming rollers100 is a concave forming roller waisted so as to curve from both endstoward a central part 103, and they are formed so that the degree oftheir curvature gradually increases with progress from upstream towardthe downstream direction.

By the sheet glass 101 being carried along a curved conveying path thesheet glass 101 is preparatorily bent in the conveying direction, andwith the multiple pre-forming rollers 100 having different degrees ofcurvature the sheet glass is gradually bent preparatorily in theconveying face width direction.

In FIG. 13B, multiple upper and lower forming rollers 105, 106 arearrayed on a conveying path with an uphill gradient downstream of thepre-forming rollers 100, and the preparatorily bent sheet glass 101 ispinched while carried by the multiple upper and lower forming rollers105, 106.

Each of the upper forming rollers 105 is a convex forming roller bulgingin a curve with progress from both its ends toward a central part 107.The upper forming rollers 105 are formed so that their degrees ofcurvature increase gradually in the downstream direction. Each of thelower forming rollers 106 is a concave forming roller waisted in a curvefrom both ends toward a central part 108. The lower forming rollers 106are formed so that their degrees of curvature increase gradually in thedownstream direction.

By the sheet glass 101 being pinched while carried between the upper andlower forming rollers 105, 106, the sheet glass 101 is bent further inthe conveying direction and bent further in the conveying face widthdirection. The sheet glass 101 is formed into a complex shape glass.

However, with the technology of JP-A-54-85217, because rollers havingtheir central parts waisted in a curve are used as pre-forming rollers,the maximum diameter D1 of the pre-forming rollers is large and it isnecessary for the roller pitch of the pre-forming rollers to be madelarge. And because consequently the distance of the conveying path forperforming pre-forming becomes long, when this technology is applied toa thin sheet glass, a temperature drop of the sheet glass becomes largeby the time the sheet glass 101 reaches the upper and lower formingrollers 105 and 106, and it becomes difficult for the thin sheet glassto be bent with good accuracy with the upper and lower forming rollers105, 106.

Also, when the edges of the sheet glass 101 are positioned betweenrollers, the edges of the sheet glass 101 are supported in acantilevered state, and the hot and soft sheet glass 101 droops easilyunder its own weight. Accordingly, it is necessary for the pitch betweenrollers to be made small to prevent this drooping.

However, in the technology of JP-A-54-85217, because the upper formingrollers 105 are formed convexly and the lower forming rollers 106 areformed concavely, the maximum diameter D2 of the upper forming rollers105 and the maximum diameter D3 of the lower forming rollers 106 arelarge. Consequently, it is necessary for the inter-roller pitch of theforming rollers 105, 106 to be made large, and positions relatively farfrom the edges are supported by the upper and lower rollers. Because ofthis, there is a risk of the edge vicinities of the sheet glass 101 notbeing bent and remaining straight, and it becomes difficult for thefront and rear sides of the sheet glass 101 to be bent with goodaccuracy.

On the other hand, in JP-A-3-174334, technology is proposed wherebyupper and lower pipes themselves are curved to make curved rollers, andby a sheet glass heated to near its softening temperature being pinchedwhile carried between these upper and lower curved rollers the sheetglass is bent in a conveying direction and a conveying face widthdirection simultaneously.

These curved rollers are curved pipes each made by holding a straighthollow metal pipe at both ends and pushing the ends to bend the hollowmetal pipe to a curve. The curved roller rotates about the curved centeraxis of the pipe.

To rotate a curved pipe with a pushing force applied to both its endswhile maintaining the curved shape of the curved pipe like this isdifficult, and there is a possibility of the curved pipe decentering.When decentering accompanies rotation of a curved pipe, it becomesdifficult to keep the spacing between upper and lower curved pipesfixed. Consequently, the spacing between the upper and lower curvedpipes widens and narrows, and there is a risk of this leading todeterioration in sheet glass forming accuracy and leading to theoccurrence of irregularities in the sheet glass surface.

Also, because a hollow metal pipe is bent to a curve by a pushing forcebeing applied to the ends of the hollow metal pipe only, it is difficultto bend the hollow metal pipe to the required curved shape with goodaccuracy, and there is a risk of this leading to deterioration in sheetglass forming accuracy.

So, a method has been awaited with which it is possible to obtain asheet glass complexly bent with high accuracy by bending a sheet glassaccurately in a conveying direction and also bending the sheet glassaccurately in its conveying face width direction.

DISCLOSURE OF THE INVENTION

The present invention provides a complex shape sheet glass formingmethod, including: a step of heating a horizontal sheet glass to nearits softening temperature; a step of bending the sheet glass in aconveying direction by pinching while conveying the heated sheet glasswith a plurality of straight rollers disposed above and below it; and astep of bending the sheet glass in a direction perpendicular to theconveying direction by pinching while conveying the sheet glass bent inthe conveying direction with a convex forming roller with its centerbulging in a curve and a concave forming roller with its center waistedin a curve, to obtain a complex shape glass.

Also, the invention provides a complex shape sheet glass formingapparatus for heating a horizontal sheet glass to near its softeningtemperature and then complexly bending this sheet glass with rollers ina conveying direction of the sheet glass and a direction perpendicularto the conveying direction, comprising: a first forming part havingmultiple upper and lower straight rollers disposed above and below theheated sheet glass for bending the sheet glass in the conveyingdirection by pinching while conveying the sheet glass; and a secondforming part having a convex forming roller with its center bulging in acurve and a concave forming roller with its center waisted in a curvefor forming a complex shape glass by bending the sheet glass bent in theconveying direction by these upper and lower straight rollers in thedirection perpendicular to the conveying direction by pinching whileconveying the sheet glass.

Here, with straight rollers, the roller diameter can be kept smallcompared to convex forming rollers and convex forming rollers describedin related art. So, the bending of the sheet glass in the conveyingdirection is carried out with straight rollers. By using straightrollers in the first forming part like this, because it is possible tokeep the roller pitch small, it is possible to make the conveyingdistance of the straight rollers short. Therefore, even when bending athin sheet glass, it is possible to convey the sheet glass to the convexforming rollers and concave forming rollers constituting the secondforming part with its temperature maintained.

Also, by using straight rollers in the first forming part and keepingthe roller pitch small, it is possible to sandwich the edge vicinitiesof the sheet glass with the straight rollers and it is possible to bendthe edges and the edge vicinities of the sheet glass with good accuracyin the conveying direction.

Then, by the sheet glass bent in the conveying direction being pinchedwhile carried with the convex forming rollers and the concave formingrollers of the second forming part, the sheet glass is bent in adirection perpendicular to the conveying direction. By the sheet glassbeing bent in the direction perpendicular to the conveying direction byconvex and concave forming rollers, the sheet glass can be bent in thedirection perpendicular to the conveying direction with good accuracy.

Preferably, the convex forming rollers are made by arraying multiplesegment rollers on a straight shaft, and the concave forming rollers aremade by arraying multiple segment rollers on a straight shaft. In thiscase, the multiple segment rollers each rotate about the respectivestraight shaft with good accuracy, and for example it is possible tokeep the gaps between the convex forming rollers and the concave formingrollers fixed. Preferably, some or all of the multiple segment rollersare freely rotatable with respect to the respective straight shaft. Inthis case, even when the circumferential lengths of the multiple segmentrollers differ, because the segment rollers rotate individually, thecircumferential speeds of the segment rollers can be matched to theconveying speed of the sheet glass. As a result, abrasions caused bycircumferential speed differences do not arise in the surface of thesheet glass.

Preferably, the respective curvatures of the complex shape glass in itsconveying direction and the direction perpendicular to the conveyingdirection are of circular arc form and the radius of curvature in theconveying direction is set smaller than the radius of curvature in thedirection perpendicular to the conveying direction. Because first thesheet glass is deeply bent in the conveying direction and then isshallowly bent in the direction perpendicular to the conveyingdirection, a complex shape glass can be formed just by adding one or twoupper-lower pairs of bending rollers for bending in the directionperpendicular to the conveying direction to a bending apparatus ofrelated art.

Preferably, in the forming of this invention, rapid cooling of thecomplex shape glass is carried out in a tempering part while the curvedshape of the complex shape glass is maintained by it being pinched whilecarried further with upper and lower curved rollers. In this case, theentire lower face region of the complex shape glass is supportedaccurately by lower cooling part rollers and the entire upper faceregion of the complex shape glass is supported accurately by uppercooling part rollers as the complex shape glass is quenched.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an example of complex shape glassesformed by a complex shape sheet glass forming method according to theinvention fitted as side windows glasses of a car;

FIG. 2 is a side view showing a complex shape sheet glass formingapparatus according to a first embodiment of the invention;

FIG. 3 is a perspective view of the complex shape forming apparatusshown in FIG. 2;

FIG. 4 is a front view showing a second forming part of the complexshape forming apparatus shown in FIG. 3;

FIG. 5 is an enlarged view of a part 5 shown in FIG. 4;

FIG. 6, FIG. 7, FIG. 8, FIG. 9 and FIG. 10 are views showing in order acomplex shape sheet glass forming method according to the firstembodiment of the invention;

FIG. 11 is a partially sectional front view showing a first convexforming roller and a first concave forming roller used in a secondforming part of a complex shape sheet glass forming apparatus accordingto a second embodiment of the invention;

FIG. 12 is an enlarged view of a part 12 in FIG. 11; and

FIG. 13A and FIG. 13B are views showing a related art method forcomplexly curving a sheet glass.

BEST MODE FOR CONVEYING OUT THE INVENTION

FIG. 1 shows an example of complex shape glasses formed by a complexshape sheet glass forming method according to the invention fitted asside window glasses of a car.

A complex shape glass 10 shown in FIG. 1 is a glass fitted to a frontside door 12 of a car 11. This complex shape glass 10 is a glass bent toa single radius R1 in a longitudinal direction (a conveying direction ofwhen curve formation is carried out) and bent to a single radius R2 in across direction (a direction perpendicular to the conveying direction)or bent complexly to a plurality of radii (for example a maximum radiusR2a and a minimum radius R2b) in the cross direction.

In FIG. 1, a complex shape glass 10 bent to a single radius R2 in thecross direction is shown, and a maximum radius R2a and a minimum radiusR2b are not shown.

Also, a complex shape glass 13 shown in FIG. 1 is a glass fitted to arear door 14 of the car 11. This complex shape glass 13 is bent to asingle radius R3 in the longitudinal direction (a conveying direction ofwhen curve formation is carried out) and bent to a single radius R4 in across direction (a direction perpendicular to the conveying direction)or bent to a plurality of radii (for example a maximum radius R4a and aminimum radius R4b) in the cross direction.

In FIG. 1, a complex shape glass 13 bent to a single radius R4 in thecross direction (the direction perpendicular to the conveying direction)is shown, and a maximum radius R4a and a minimum radius R4b are notshown.

The radius R1 of the complex shape glass 10 and the radius R3 of thecomplex shape glass 13 are for example 1,500 mm; however, there is nolimitation to this.

When the complex shape glass 10 is bent to a single radius R2 in itscross direction, the single radius R2 is for example 15,000 mm; however,there is no limitation to this.

When the complex shape glass 13 is bent to a single radius R4 in itscross direction, the single radius R4 is for example 30,000 mm; however,there is no limitation to this.

In the following, a method and an apparatus for manufacturing thecomplex shape glass 10 by bending a sheet glass to a single radius R1 ina conveying direction and to a single radius R2 in a directionperpendicular to the conveying direction (hereinafter called “theconveying face width direction”) will be described.

FIG. 2 to FIG. 10 illustrate a complex shape sheet glass formingapparatus according to a first embodiment of the invention.

Referring to FIG. 2, a complex shape sheet glass forming apparatus 20 ismade up of a heating furnace 23 for heating a sheet glass 21 to near itssoftening point while conveying it horizontally with multiple rollers22; a first forming part 25 for bending in a conveying direction (thearrow A direction) the sheet glass 21 having emerged from the heatingfurnace 23; a second forming part 26 for bending in the conveying facewidth direction the sheet glass 21 bent in this first forming part 25; atempering part 27 for tempering by air cooling the complex shape glass10 bent in the conveying face width direction in this second formingpart 26; and a take-up part 28 for taking up the complex shape glass 10tempered by air cooling in the tempering part 27.

The first forming part 25 has a conveying distance L1. Straight rollers30, 31 of multiple sets constituting upper-lower pairs are disposed overthe conveying distance L1. In this figure, an example is shown whereinseven sets of straight rollers 30, 31 are disposed with a predeterminedspacing in the conveying direction on a circular arc of radius R1.

The radius R1 is an uphill gradient pointing upward from the horizontalplane of the heating furnace 23, but to show it in such a way that it iseasy to understand it is drawn gently sloping in FIG. 2. Adjacent upperand lower straight rollers 30, 31 are actually set narrow, but in FIG. 3to make the straight rollers 30, 31 easy to understand the rollerspacing is shown relatively large.

The upper straight rollers 30 and the lower straight rollers 31 areconnected to a rotary drive source not shown in the drawings. By thisrotary drive source being driven, the upper and lower straight rollers30, 31 are rotated and a sheet glass 21 pinched between the upperstraight rollers 30 and the lower straight rollers 31 is carried.

As shown in FIG. 3, by using the straight rollers 30, 31 in the firstforming part 25 it is possible to keep the adjacent roller pitch small,and the conveying distance L1 of the first forming part 25 can be keptshort. When the conveying distance L1 is short, even when bending a thinsheet glass, the sheet glass is carried to the second forming part 26with its temperature maintained, and the sheet glass can be bent withgood accuracy in the conveying face width direction in the secondforming part 26.

Also, when the roller pitch of the first forming part 25 is kept small,the edge vicinities of the sheet glass 21 are pinched surely by theupper and lower straight rollers 30, 31. Therefore, the edges and edgevicinities of the sheet glass 21 are bent with good accuracy in theconveying direction.

The second forming part 26 has a first convex forming roller 33 whosecentral part bulges in the form of a curve, a first concave formingroller 34 whose central part is waisted in a curve, a second convexforming roller 35 whose central part bulges in a curve, and a secondconcave forming roller 36 whose central part is waisted in a curve. Thefirst convex forming roller 33 and the first concave forming roller 34,which form an upper-lower pair, constitute first forming rollers. Thesecond convex forming roller 35 and the second concave forming roller36, which form an upper-lower pair, constitute second forming rollers.

The sheet glass 21 bent in the conveying direction in the first formingpart 25 is pinched while carried and bent in the conveying face widthdirection by the convex forming rollers 33, 35 and the concave formingrollers 34, 36.

When the bending of the sheet glass 21 in the conveying face widthdirection is small, the predetermined bending is carried out with thefirst forming rollers only.

The tempering part 27 has multiple lower tempering part curved rollers(lower curved rollers) 38, multiple upper tempering part curved rollers(upper curved rollers) 39, a lower tempering part nozzle box 40 disposedbelow the lower tempering part curved rollers 38, and an upper temperingpart nozzle box 41 disposed above the upper tempering part curvedrollers 39.

The lower tempering part curved rollers 38 and the upper tempering partcurved rollers 39 are connected to a rotary drive source not shown inthe figures, and by the rotary drive source being driven the temperingpart curved rollers 38, 39 are rotated. The complex shape glass 10 ispinched and carried between the lower tempering part curved rollers 38and the upper tempering part curved rollers 39.

By air being supplied from an air supply pump 65 to the lower temperingpart nozzle box 40, this air is blown through multiple air nozzles 66 atthe complex shape glass 10.

By air being supplied from the air supply pump 65 to the upper temperingpart nozzle box 41, this air is blown through multiple air nozzles 68 atthe complex shape glass 10.

That is, the complex shape glass 10 is air-cooled by the upper and lowernozzle boxes 41, 40.

The upper and lower tempering part curved rollers 39, 38 sandwich thecomplex shape glass 10. The upper and lower tempering part curvedrollers 39, 38 are curved to a radius R2. These upper and lowertempering part curved rollers 39, 38 are disposed at a predeterminedspacing along a conveying path of radius R1. Accordingly, the complexshape glass 10 is air-cooled while being held in a predetermined bentstate and is manufactured with good accuracy.

FIG. 4 shows the first convex forming roller 33 and the first concaveforming roller 34 of the second forming part 26 shown in FIG. 3.

The first concave forming roller 34 is made up of multiple segmentrollers, twelve segment rollers 43A to 43L in the embodiment shown inFIG. 4, and a straight shaft 44 on which the segment rollers 43A to 43Lare fitted. The segment rollers 43A to 43L are arranged so that thecentral part narrows in a curve. Thrust plates 45 are interposed betweenthe adjacent segment rollers 43A to 43L.

The straight shaft 44 is supported horizontally by having its left andright ends attached to left and right bearings 46, 47 provided on leftand right support members 48, 49.

The segment rollers 43A to 43L are rotatably attached to the straightshaft 44 via bushes 50 provided on the straight shaft 44. By themultiple segment rollers 43A to 43L being fitted on the straight shaft44, as a whole they form a curved circumferential surface (concavecircumferential surface) of radius R2A.

The surfaces of the segment rollers 43A to 43L are covered with aheat-resistant covering material (band material or felt material) 51such as for example Kevlar “registered trade mark of Dupont Co.” (a paraaramide fiber) and thereby made to have a cushion effect. By this means,the occurrence of defects such as contact marks in the surface of thecomplex shape glass 10 is prevented.

The first convex forming roller 33 is made up of multiple segmentrollers, twelve segment rollers 53A to 53L in the embodiment shown inFIG. 4, and a straight shaft 54 on which the segment rollers 53A to 53Lare fitted. The segment rollers 53A to 53L are arranged so that acentral part protrudes in a curve. Thrust plates 55 are interposedbetween the adjacent segment rollers 53A to 53L.

The straight shaft 54 is supported horizontally by having its left andright ends attached to left and right bearings 56, 57 mounted on leftand right support members 60, 61 via adjusting bolts 58, 58. Theadjusting bolts 58, 58 raise and lower the first convex forming roller33 to adjust the gap S between the first convex forming roller 33 andthe first concave forming roller 34 to match the thickness t (see FIG.2) of the sheet glass 21.

The segment rollers 53A to 53L are rotatably fitted on the straightshaft 54 via multiple bushes 62 provided on the straight shaft 54. Bythe multiple segment rollers 53A to 53L being fitted on the straightshaft 54, as a whole they form a circumferential surface with itscentral part curved convexly (a convex circumferential surface).

Here, the radius in the conveying face width direction of the firstconvex forming roller 33 is the value obtained by subtracting thethickness t of the complex shape glass 10 from the radius R2A of thefirst concave forming roller 34, i.e. R2A−t.

The surfaces of the segment rollers 53A to 53L are covered with aheat-resistant covering material (band material or felt material) 63such as for example the above-mentioned Kevlar, and thereby made to havea cushion effect. By this means, the occurrence of defects such ascontact marks in the surface of the complex shape glass 10 is prevented.

Returning to FIG. 3, the second concave forming roller 36 is of the sameconstruction as the first concave forming roller 34, and has multiplesegment rollers 73A to 73L (see FIG. 8). These segment rollers 73A to73L are fitted on a straight shaft not shown in the drawings. The secondconcave forming roller 36 as a whole has a circumferential surface ofradius R2 with its central part curved concavely (concavecircumferential surface).

The second convex forming roller 35 is of the same construction as thefirst convex forming roller 33, and has multiple segment rollers 74A to74L (see FIG. 8). These segment rollers 74A to 74L are fitted on astraight shaft not shown in the drawings. The second convex formingroller 35 as a whole has a circumferential surface with its central partcurved convexly (convex circumferential surface).

Here, the conveying face width direction radius of the second convexforming roller 35 is the value obtained by subtracting the thickness tof the complex shape glass 10 from the radius R2 of the second concaveforming roller 36, i.e. R2−t.

The radius R2A and the radius R2 are in the relationship radiusR2A>radius R2. Consequently, the complex shape glass 10 is bent to aboutthe middle of the target curvature by the first convex forming roller 33and the first concave forming roller 34, and the complex shape glass 10is bent to the shape of the target curvature by the second convexforming roller 35 and the second concave forming roller 36.

As a result of the segment rollers 53A to 53L and 43A to 43L of thefirst convex forming roller 33 and the first concave forming roller 34being fitted on straight shafts 54, 44, the segment rollers 53A to 53Land 43A to 43L rotate with good accuracy about the straight shafts 54,44.

As a result of the segment rollers 74A to 74L and 73A to 73L of thesecond convex forming roller 35 and the second concave forming roller 36being fitted on straight shafts, the segment rollers 74A to 74L and 73Ato 73L rotate with good accuracy about those straight shafts.

Therefore, the gap between the first convex forming roller 33 and thefirst concave forming roller 34 and the gap between the second convexforming roller 35 and the second concave forming roller 36 can be keptfixed, and the sheet glass 21 can be bent with good accuracy.

In the first embodiment, an example is shown wherein the second formingpart 26 has first and second concave forming rollers 34, 36 and firstand second convex forming rollers 33, 35; however, as another example,alternatively only the first convex forming roller 33 and the firstconcave forming roller 34, that is, the first forming rollers, may beprovided. However, in this case, the complex shape glass 10 must be bentto the shape of the target curvature with just the first convex formingroller 33 and the first concave forming roller 34.

FIG. 5 shows a part of the first convex forming roller 33 shown in FIG.4 enlarged.

When the maximum radius of the segment roller 53I is written r1, thecircumference of the segment roller 53I is 2πr1. When the maximum radiusof the segment roller 53J is written r2, the circumference of thesegment roller 53J is 2πr2. The radius r1 and the radius r2 are in therelationship radius r1>radius r2, and 2πr1>2πr2. Therefore, when thesegment roller 53I and the segment roller 53J are rotated at the sameangular speed in the direction of the arrows, the circumferential speedof the segment roller 53I and the circumferential speed of the segmentroller 53J are different, and there is a risk of defects such as contactmarks arising in the surface of the complex shape glass 10.

To avoid this, the segment rollers 53I, 53J are each freely rotatablyfitted to the straight shaft 54, so that when the complex shape glass 10contacts the surfaces of the segment rollers 53I, 53J, thecircumferential speeds of the segment rollers 53I, 53J are each matchedto the conveying speed of the complex shape glass 10. Consequently,defects such as contact marks caused by slip between the complex shapeglass 10 and the segment rollers 53I, 53J are prevented from arising inthe surface of the complex shape glass 10.

The first concave forming roller 34, the second convex forming roller 35and the second concave forming roller 36 shown in FIG. 3 are also of thesame construction as the first convex forming roller 33, and the sameeffects are obtained.

As a result of the segment rollers 53A to 53L and 43A to 43Lconstituting the first convex forming roller 33 and the first concaveforming roller 34 of the second forming part 26 shown in FIG. 4 beingrotatably fitted to the straight shafts 54 and 44, and the segmentrollers 74A to 74L and 73A to 73L constituting the second convex formingroller 35 and the second concave forming roller 36 shown in FIG. 3 beingrespectively fitted rotatably to straight shafts not shown in thefigures, there is no need for the second forming part 26 to have drivingmeans for conveying the complex shape glass 10.

Because the second forming part 26 only has two sets of forming rollersdisposed in the conveying path, the first forming rollers consisting ofthe upper-lower pair of the first convex forming roller 33 and the firstconcave forming roller 34 and the second forming rollers consisting ofthe upper-lower pair of the second convex forming roller 35 and thesecond concave forming roller 36, the conveying distance L2 (see FIG. 2)of the second forming part 26 can be kept relatively short. Therefore,the complex shape glass 10 is carried by utilizing the rotary drivingforce of the multiple straight rollers 30, 31 of the first forming part25 disposed upstream of the second forming part 26 and the multipletempering part curved rollers 38, 39 of the tempering part 27 disposeddownstream of the second forming part 26.

However, in this invention, alternatively, the second forming part 26may be provided with driving means, to convey the complex shape glass 10positively.

Explaining this specifically, a construction is adopted such that rotarydriving power can be transmitted from driving means through the straightshaft 44 to the two central segment rollers 43F, 43G positioned in thecentral part of the first concave forming roller 34 shown in FIG. 4, andthe other segment rollers 43A to 43E and 43H to 43L are freely rotatablyfitted to the straight shaft 44. Also, a construction is adopted suchthat rotary driving power can be transmitted from driving means throughthe straight shaft 54 to the two central segment rollers 53F, 53Gpositioned in the central part of the first convex forming roller 33,and the other segment rollers 53A to 53E, 53H to 53L are freelyrotatably fitted to the straight shaft 54.

In this example also, when the complex shape glass 10 is carried by therotary driving force of the central segment rollers 43F, 43G, 53F and53G, the circumferential speeds of the other segment rollers 43A to 43E,43H to 43L, 53A to 53E, 53H to 53L can be matched to the conveying speedof the complex shape glass 10, and defects such as contact marks causedby slip between the complex shape glass 10 and the segment rollers donot arise in the surface of the complex shape glass 10.

Next, a complex shape sheet glass forming method according to the firstembodiment of the invention will be described with reference to FIG. 6to FIG. 10.

In FIG. 6, while a sheet glass 21 in the heating furnace 23 is carriedby the multiple rollers 22, the sheet glass 21 is heated to near itssoftening temperature. The heated sheet glass 21 is carried in thedirection shown with the arrow B while being pinched by the multipleupper and lower straight rollers 30, 31 of the first forming part 25.

Because the multiple upper and lower straight rollers 30, 31 aredisposed in the conveying direction with a predetermined spacing along acircular arc conveying path of radius R1, by being carried along theconveying path curving at the radius R1 the sheet glass 21 is bent so asto curve with the radius R1.

The sheet glass 21 bent in the conveying direction in the first formingpart 25 is carried toward the second forming part 26. That is, it iscarried as shown by the arrow C while being pinched by the first convexforming roller 33 and the first concave forming roller 34 of the secondforming part 26 shown in FIG. 7.

At this time, by the first convex forming roller 33 and the firstconcave forming roller 34, which are first forming rollers, the sheetglass 21 is bent to a curved shape of about the middle of the targetcurved shape, i.e. to a circular arc shape of the radius R2A (see FIG.3), in the conveying face width direction.

This sheet glass 21 bent to an intermediate degree is carried as shownby the arrow C while being pinched by the second convex forming roller35 and the second concave forming roller 36, which are second formingrollers.

At this time, the sheet glass 21 is bent further by the second convexforming roller 35 and the second concave forming roller 36, and is bentto the shape of the target curvature, i.e. to a circular arc shape ofradius R2 (see FIG. 3) in the conveying face width direction.

Thus, first, the sheet glass 21 is complexly bent by being bent in theconveying direction in the first forming part 25 and then being bent inthe conveying face width direction in the second forming part 26.

Then, as shown in FIG. 8, a complex shape glass 10 is formed by thesheet glass 21 (see FIG. 7) being bent to a circular arc shape of radiusR2 by the second convex forming roller 35 and the second concave formingroller 36.

In FIG. 9, the formed complex shape glass 10 is carried in the directionshown by the arrow D while being pinched by the lower tempering partcurved rollers 38 and the upper tempering part curved rollers 39 of thetempering part 27.

Here, because the upper and lower tempering part curved rollers 39, 38follow a circular arc of radius R2 (see FIG. 3), and these upper andlower tempering part curved rollers 39, 38 are disposed at apredetermined spacing along a circular arc of radius R1 (see FIG. 2 andFIG. 3), the complex shape glass 10 is held in the required bent shapeas it is carried.

At this time, by air being supplied from the air supply pump 65 to thelower tempering part nozzle box 40, air is blown out toward the complexshape glass 10 through the multiple air nozzles 66 as shown with arrows.At the same time, by air being supplied from the air supply pump 65 tothe upper tempering part nozzle box 41, air is blown out toward thecomplex shape glass 10 through the multiple air nozzles 68 as shown witharrows. The complex shape glass 10 is tempered by air-cooling whilebeing held in the required bent shape.

As shown in FIG. 10, the complex shape glass 10 tempered by air-coolingin the tempering part 27 is taken up by the take-up part 28 and carriedin the arrow E direction by multiple rollers 29 of the take-up part 28.

Here, the respective curvatures of the complex shape glass 10 in theconveying direction and the conveying face width direction are circulararc shapes, and the conveying direction radius of curvature R1 issmaller than the conveying face width direction radius of curvature R2.Because the conveying direction radius of curvature R1 is smaller thanthe conveying face width direction radius of curvature R2, the complexshape glass 10 can be formed just by adding one or two pairs ofconveying face width direction bending rollers to a bending apparatus ofrelated art.

Next, a complex shape forming apparatus and method of a secondembodiment of the invention will be described with reference to FIGS. 11and 12.

A complex shape sheet glass forming apparatus 80 according to a secondembodiment shown in FIG. 11 differs from the first embodiment only inthat its second forming part 81 is made up of a first concave formingroller 82 and a first convex forming roller 83 and a second concaveforming roller and a second convex forming roller not shown in thedrawings, and the rest of its construction is the same as that of thefirst embodiment.

The first concave forming roller 82 has tubular ring rollers (segmentrollers) 84A to 84X of different diameters rotatably fitted to astraight shaft 85. By the width of the ring rollers 84A to 84X beingmade narrow, the ring rollers 84A to 84X can be made cylindrical inshape.

Of the tubular ring rollers 84A to 84X of different diameters,small-diameter ring rollers 84L, 84M are disposed centrally, and theother ring rollers 84A to 84K and 84N to 84X are disposed so that theirdiameters gradually increase from the center toward the left and rightends. By this means, a first concave forming roller 82 having anapproximately curved shape with the central part of the first concaveforming roller 82 made concave is obtained.

The first convex forming roller 83 has tubular ring rollers (segmentrollers) 86A to 86X of different diameters rotatably fitted to astraight shaft 87. By the width of the ring rollers 86A to 86X beingmade narrow, the ring rollers 86A to 86X can be made cylindrical inshape.

Of the tubular ring rollers 86A to 86X of different diameters,large-diameter ring rollers 86L, 86M are disposed centrally, and theother ring rollers 86A to 86K and 86N to 86X are disposed so that theirdiameters gradually decrease from the center toward the left and rightends. By this means, a first convex forming roller 83 having anapproximately convex curved shape with the central part of the firstconvex forming roller 83 bulging convexly is obtained.

As shown in FIG. 12, the first concave forming roller 82 has thrustplates 88 interposed between the adjacent ring rollers 84A to 84X (only84P to 84U are shown). Each of the ring rollers 84A to 84X is rotatably(freely) fitted to the straight shaft 85 by way of a bush 89.

Each of the ring rollers 84A to 84X has around its periphery aheat-resistant covering material (band material or felt material) 90such as for example Kevlar, and is thereby given a cushion effect.Defects such as contact marks are thereby prevented from arising in thesurface of the complex shape glass 10.

The first convex forming roller 83 has thrust plates 91 interposedbetween the adjacent ring rollers 86A to 86X (only 86P to 86U areshown). Each of the ring rollers 86A to 86X is rotatably (freely) fittedto the straight shaft 87 by way of a bush 92.

Each of the ring rollers 86A to 86X has around its periphery aheat-resistant covering material (band material or felt material) 93such as for example Kevlar, and is thereby given a cushion effect.Defects such as contact marks are thereby prevented from arising in thesurface of the complex shape glass 10.

Here, the second concave forming roller and the second convex formingroller also are of the same construction as the first concave formingroller 82 and the first convex forming roller 83. Therefore, in thesecond embodiment also, the same effects as those of the firstembodiment are obtained.

Although in the first and second embodiments an example was describedwherein the complex shape glass 10 was tempered by air-cooling in atempering part 27, there is no limitation to this, and it is alsopossible to cool the complex shape glass 10 gradually by blowing air atit weakly.

Also, although in the first and second embodiments examples weredescribed wherein the shape of the complex shape glass 10 is such thatits conveying direction curvature is the same radius R1 and itscurvature in the direction perpendicular to the conveying direction isthe same radius R2 and there is the relationship radius R1<radius R2,there is no need for limitation to radius R1<radius R2.

Furthermore, whereas in the complex shape glass 10 of the first andsecond embodiments examples were described wherein the curvature in thedirection perpendicular to the conveying direction was bent to acircular arc of a single radius R2, the curvature in the directionperpendicular to the conveying direction is not limited to a circulararc. That is, the curvature in the direction perpendicular to theconveying direction of the complex shape glass 10 may alternatively be ashape curved complexly to a plurality of radii, and in short may be anycurved shape.

INDUSTRIAL APPLICABILITY

By using multiple straight rollers on a curved conveying path and makingthe pitch between the rollers short and thereby making the conveyingdistance of the straight rollers short, even when bending a thin sheetglass it is possible to convey the sheet glass to the next bending stepwith its temperature maintained and it is possible to bend the sheetglass with good accuracy in a conveying direction and a directionperpendicular to the conveying direction. Because of this, the inventionis useful in for example manufacturing complex shape glass havingdifferent radii of curvature longitudinally and across. For example itis useful in the manufacture of window glasses used in cars and thelike.

1. A complex shape sheet glass forming method, including the steps of: astep of heating a horizontal sheet glass to near its softeningtemperature; a step of bending the sheet glass in a conveying directionby pinching while conveying the heated sheet glass with a plurality ofstraight rollers disposed above and below it; and a step of bending thesheet glass in a direction perpendicular to the conveying direction bypinching while conveying the sheet glass bent in the conveying directionwith a convex forming roller with its center bulging in a curve and aconcave forming roller with its center waisted in a curve, to obtain acomplex shape glass.
 2. The complex shape sheet glass forming methodaccording to claim 1, wherein the convex forming roller comprisesmultiple segment rollers arrayed on a straight shaft and the concaveforming roller comprises multiple segment rollers arrayed on a straightshaft.
 3. The complex shape sheet glass forming method according toclaim 2, wherein at least some of the multiple segment rollers arefreely rotatable with respect to the respective straight shaft.
 4. Thecomplex shape sheet glass forming method according to claim 1, whereinthe respective curvatures of the complex shape glass in the conveyingdirection and the direction perpendicular to the conveying direction areof circular arc form and the radius of curvature in the conveyingdirection is smaller than the radius of curvature in the directionperpendicular to the conveying direction.
 5. The complex shape sheetglass forming method according to claim 1, further including a step ofquenching the complex shape glass while maintaining the curved shape ofthe complex shape glass by pinching while conveying it further withupper and lower curved rollers.
 6. The complex shape sheet glass formingapparatus for heating a horizontal sheet glass to near its softeningtemperature and then complexly bending this sheet glass with rollers ina conveying direction of the sheet glass and a direction perpendicularto the conveying direction, comprising: a first forming part havingmultiple upper and lower straight rollers disposed above and below theheated sheet glass for bending the sheet glass in the conveyingdirection by pinching while conveying the sheet glass; and a secondforming part having a convex forming roller with its center bulging in acurve and a concave forming roller with its center waisted in a curvefor forming a complex shape glass by bending the sheet glass bent in theconveying direction by these upper and lower straight rollers in thedirection perpendicular to the conveying direction by pinching whileconveying the sheet glass.
 7. The complex shape sheet glass formingapparatus according to claim 6, wherein the convex forming rollercomprises multiple segment rollers arrayed on a straight shaft and theconcave forming roller comprises multiple segment rollers arrayed on astraight shaft.
 8. The complex shape sheet glass forming methodaccording to claim 7, wherein at least some of the multiple segmentrollers are freely rotatable with respect to the respective straightshaft.
 9. The complex shape sheet glass forming apparatus according toclaim 6, so constructed that the respective curvatures of the complexshape glass in the conveying direction and the direction perpendicularto the conveying direction are formed in a circular arc shape and soconstructed that the radius of curvature of the complex shape glass inthe conveying direction is smaller than the radius of curvature in thedirection perpendicular to the conveying direction.
 10. The complexshape sheet glass forming method according to claim 6, furthercomprising a tempering part for quenching the complex shape glass formedwith the convex forming roller and the concave forming roller whilemaintaining the shape of the complex shape glass by pinching whileconveying it with curved rollers.